Of the 1.1 million Americans who are currently infected with HIV, it is estimated that 232,700 remain unaware of their infection and 38% testing positive for HIV do so within one year of receiving an AIDS diagnosis. Furthermore, an estimated 4.1 million Americans have been infected with the hepatitis C virus (HCV), including 3.2 million with chronic HCV;the proportion unaware of their infection is unknown. Although substance users are at substantially increased risk for HIV and HCV infection, and for HIV/HCV co-infection, fewer than half of U.S. drug treatment programs currently offer HIV testing on-site and fewer than 40% offer HCV testing on-site. New recommendations from the Centers for Disease Control and Prevention (CDC) recommend routine HIV screening of all adults in all health care settings, and expanded HIV testing in alternative settings such as drug abuse treatment programs;these initiatives may also represent an opportunity to expand HCV testing using a newly-developed rapid HCV test. On a practical level, however, lack of reimbursement for HIV testing is a formidable barrier to implementing recommendations for expanded testing. CTN 0032 is a NIDA-sponsored randomized controlled clinical trial that is assessing the relative effectiveness of three HIV testing strategies in drug treatment settings where HIV testing has not previously been offered. Participants screened for and enrolled in CTN 0032 also report whether they were previously tested for HCV and their HCV status, if known. We propose to conduct an ancillary study to CTN 0032 with the following specific aims: 1) to determine the costs to drug treatment programs of on-site rapid HIV testing with counseling, on-site rapid testing without counseling, and referral for off-site testing, and to compare these costs to those derived from the societal perspective;2) to evaluate the cost-effectiveness of the three HIV testing strategies in drug treatment settings, using the Cost-Effectiveness of Preventing AIDS Complications (CEPAC) computer simulation model;3) to project the cost and cost-effectiveness in drug treatment settings of on-site rapid HCV testing in combination with rapid HIV testing and on its own. An economic evaluation has not previously been conducted alongside a randomized clinical trial of HIV testing strategies in non-medical settings. Cost data will be derived from CTN 0032 study records and additional data collected during site visits while the trial is being completed. Results of the cost analysis (Aim 1) will address the immediate practical concern about reimbursement as a barrier to HIV testing in non-medical settings, enabling programs to assess budgetary requirements for testing programs. The cost-effectiveness analysis (Aim 2) will assist policymakers in determining the relative value of different HIV testing programs in drug treatment settings, and to compare the cost-effectiveness of these programs to HIV testing in other settings and to other health care investments. Projecting the cost and cost-effectiveness of rapid HCV testing with or without HIV testing (Aim 3) will assist programs in evaluating this option, and will inform the design of a future randomized trial of HCV rapid testing. PUBLIC HEALTH RELEVANCE: This research will enable drug treatment programs that are not currently offering HIV testing to their clients to assess the budgets required to implement different testing programs to improve early HIV detection, alone or in combination with hepatitis C testing, so that they can advocate for appropriate reimbursement. Advocating for reimbursement, however, also requires evidence that the additional costs are an efficient use of resources. By conducting a cost-effectiveness analysis alongside a clinical trial of HIV testing in drug treatment programs, the research will also assist policymakers in determining the "value for money" of different HIV testing programs within drug treatment settings, and to compare the cost-effectiveness of these programs to HIV testing in other settings and to other health care investments.